Enhancing the emission spectrum of light-based dermatologic treatment devices

ABSTRACT

A dermatologic treatment device having a light source emitting optical radiation having a plurality of wavelengths. The optical radiation including light exhibiting at least a first set of wavelengths and a second set of wavelengths, in which the first set of wavelengths is preferred for a dermatologic treatment. The dermatologic treatment device further including a wavelength converter for converting at least some of the second set of wavelengths of the optical radiation to the first set of wavelengths. A contact element is also included for conveying at least some of the converted optical radiation to a skin surface to facilitate the dermatologic treatment.

RELATED APPLICATIONS

This claims priority to and the benefit of U.S. Provisional PatentApplication No. 61/035,508 filed on Mar. 11, 2008, the entirety of whichis incorporated herein by reference.

TECHNICAL FIELD

The disclosed technology relates generally to dermatologic treatmentsand more specifically to techniques for enhancing the performance ofoptical radiation systems used in such dermatologic treatments.

BACKGROUND

Electromagnetic energy has been used in a wide range of medicalapplications for many years. In the field of dermatology, lasers,flashlamps/intense pulsed light systems (IPL), and other sources ofelectromagnetic radiation, particularly in the optical radiationwavebands, have been used for permanently and temporarily removing hair,promoting hair regrowth, coagulating blood vessels visible through apatient's skin, treating lesions, removing port-wine stains, removingtattoos, rejuvenating skin, and the like. Optical radiation systemsapplied to such dermatologic treatments are normally operated by trainedprofessionals who select the preferred energy level, wavelength(s), andother optical radiation parameters that are optimal for a particulartreatment, given a patient's skin type and other factors, so as toeffectuate the desired treatment while mitigating damage to nontargettissue.

The ability to safely and efficiently service multiple patients ofvarying skin types and/or perform multiple types of dermatologictreatments comes at a significant cost, with many clinical systems inexistence today exhibiting a price exceeding $50,000. Industryparticipants in this highly competitive market are constantly trying tobalance the flexibility, efficacy, and safety of such systems withcost-reduction goals. Recent attempts to commercialize single-purposedermatologic systems (e.g., for hair growth management and removal, hairregrowth, or skin rejuvenation) for the home-use, mass market haveexperienced limited success, with such relatively low-cost systemseither still being too expensive for many consumers or exhibiting poorefficacy. Accordingly, continuing research and development is necessaryto develop cost-effective, safe, and effective dermatologic treatmentsystems regardless of market segment.

SUMMARY

In one aspect, the disclosed technology can be used to enhance thebrightness of a multi-wavelength light source incorporated within adermatologic system to thereby increase its efficiency and reduce thepower and filtering requirements of the system resulting in an overallreduction in the size and cost of the system. Other aspects of thedisclosed technology can enhance a user's experience with thedermatologic system by reducing the user's pain sensation when using thesystem during a dermatologic treatment and/or facilitating the movementof the system across a skin surface under treatment.

In one illustrative embodiment, the disclosed technology can be used toenhance the optical radiation applied to a skin surface to facilitate adermatologic treatment. In such an embodiment, a light source isprovided which emits optical radiation having multiple wavelengths,where such emitted light has a first set of wavelengths that ispreferred for a particular dermatologic treatment as well as other setsof wavelengths that are less desirable/undesirable for the treatment. Atleast some of the optical radiation exhibiting such undesirablewavelengths is reflected back to the light source to enhance the overallbrightness of the emitted optical radiation. The enhanced opticalradiation can be filtered to substantially remove any light exhibitingthe undesirable wavelengths from the enhanced optical radiation appliedto the skin surface during the dermatologic treatment. Alternatively, atleast some of the light exhibiting the undesirable wavelengths can beconverted into light exhibiting the preferred first set of wavelengthsprior to application of the enhanced optical radiation to the skinsurface. The optical radiation applied to the skin surface can furtherbe diffused. The light source itself can be automatically energized atpredetermined intervals during the dermatologic treatment to, forexample, produce a strobe effect. Emission of optical radiation may alsobe enabled in response to detecting a contact with the skin surface.Further, a vibration can be applied to the skin surface to reduce thepain sensation experienced by a user/patient during the dermatologictreatment.

In another illustrative embodiment, the disclosed technology is embodiedwithin a system adapted to enhance the brightness of optical radiationapplied to a skin surface to facilitate a dermatologic treatment. Thedisclosed system includes a first reflector that reflects at least someoptical radiation (preferably exhibiting multiple wavelengths) emittedby a light source (e.g., one or more flashlamps, one or morelight-emitting diodes, etc.) back to the light source so as to enhancethe brightness of the emitted optical radiation. At least some of theenhanced optical radiation is conveyed through a contact element incontact with a skin surface to facilitate a desired dermatologictreatment.

In some dermatologic treatments (e.g., permanent/temporary hairremoval), the enhanced optical radiation includes at least somewavelengths in the near infrared portion of the electromagneticspectrum. The optical radiation may exhibit sets of wavelengths that arepreferable for different dermatologic treatments. For example, a firstset of wavelengths may be preferred for a particular dermatologictreatment, such as hair removal, while a second set of wavelengths maybe preferred for a different dermatologic treatment, such as treatmentof psoriasis. The optical radiation reflected by the reflector back tothe light source may include all wavelengths, primarily the set ofwavelengths that are not desired for a particular dermatologictreatment, or any other combination of wavelengths.

A particularly advantageous arrangement for this illustrative embodimentwould have the first reflector reflect primarily undesirable wavelengthsets back to the light source and allow optical radiation exhibiting afirst set of preferred wavelengths to pass the reflector without anysubstantially material affect. In this embodiment, a second reflectorcan be positioned to reflect at least some of the optical radiationexhibiting the first set of preferred wavelengths towards the skinsurface. The first reflector may be further arranged in a tubular shapethat substantially surrounds the light source and the second reflectormay be preferably arranged in an ellipsoid shape. Alternatively, thefirst reflector may be arranged in a planar shape and the secondreflector may be arranged in a paraboloid shape.

The contact element that is in contact with the skin surface during thedermatologic treatment is configured to be optically transparent to theoptical radiation exhibiting the first set of preferred wavelengths. Thecontact element may include a hydrophilic portion that facilitates thedermatologic treatment (e.g., facilitates gliding of the dermatologicsystem over the skin surface being treated) and may further diffuse theoptical radiation conveyed by the contact element when the hydrophilicportion is exposed to water. The disclosed system may further include atiming circuit to energize the light source at predetermined intervalsduring the dermatologic treatment, a contact sensor detecting a contactbetween the contact element and the skin surface and adapted to transmita control signal in response to such contact to enable the light sourceto be energized, and/or a vibrating element adapted to apply a vibrationto the skin surface to reduce pain sensation experienced by auser/patient during the dermatologic treatment. In a particularlyadvantageous arrangement, the contact element both conveys opticalradiation having a preferred set of wavelengths to which it is opticallytransparent and applies the vibration to the skin surface being treatedto reduce the pain sensation experienced by the user/patient during thedermatologic treatment.

In yet another illustrative embodiment, the disclosed technology isembodied within a system that includes a light source, abrightness-enhancing element in optical communication with the lightsource, and a contact element adapted to be in contact with the skinsurface being treated by the dermatologic treatment system. The lightsource emits optical radiation (e.g., with at least one wavelength inthe near infrared portion of the electromagnetic spectrum) that isbeneficial to the dermatologic treatment and the brightness-enhancingelement is adapted to increase the brightness of this emitted opticalradiation during the treatment. The contact element is adapted toprovide a vibration to the skin surface to reduce a pain sensationresulting from application of the brightness-enhanced optical radiationto the skin surface. The disclosed system further includes a handheldhousing that contains the light source and brightness-enhancing elementand is configured to maintain a relative orientation between the lightsource, brightness-enhancing element, and contact element during thedermatologic treatment.

In yet another illustrative embodiment, the disclosed technology can beembodied within a system that includes an electromagnetic sourceemitting electromagnetic radiation (e.g., optical radiation) that isbeneficial to a dermatologic treatment, a vibration element thatprovides a vibration to a skin surface to reduce a sensation resultingfrom application of the electromagnetic radiation to the skin surfaceduring the dermatologic treatment, and a handheld housing that containsthe electromagnetic source and maintains a relative orientation betweensuch source and the vibration element during the dermatologic treatment.The vibration element may also be contained within the handheld housingand/or may further provide a haptic feedback to the user of the system.The haptic feedback substantially coincides with the application of theemitted optical radiation to the skin surface during the dermatologictreatment.

In yet another illustrative embodiment, the disclosed technology can beembodied within a system that includes a source of electromagneticradiation that is beneficial to a dermatologic treatment. This systemfurther includes a contact element that facilitates conveyance of atleast some of the electromagnetic radiation emitted by the source to askin surface and where the contact element preferably includes ahydrophilic portion that facilitates its movement to/onto the skinsurface. The hydrophilic portion of the contact element can also beformulated to filter at least some of the electromagnetic radiation tosubstantially inhibit conveyance of at least some undesirablewavelengths to the skin surface. The hydrophilic portion can alsodiffuse the electromagnetic energy prior to its conveyance to the skinsurface.

In yet another illustrative embodiment, the disclosed technology can beembodied within a dermatologic treatment device that includes at least alight source (e.g., one or more flashlamps and/or light emittingdiodes), a wavelength converter, and a contact element. The light sourceemits optical radiation exhibiting a first set of wavelengths (e.g., atleast some of such wavelengths can be in the near infrared portion ofthe electromagnetic spectrum) that are preferred for a dermatologictreatment and other sets of wavelengths that are less desirable orundesirable. The wavelength converter converts at least some of theseother, less desirable/undesirable wavelengths (which may exhibit shorterwavelengths than those in the first set) into the preferred wavelengthsof the first set. The wavelength converter preferably includes acomposition of quantum dots having a core comprised of, for example,CdTe, InAs, InP, InSb, PbS, PbSe, or the like. The core of such quantumdots can be further encapsulated in one or more overcoating layerscomprised of, for example, ZnS, ZnSe, GaN, MgS, MgSe, MgTe, CdS, CdSe,or the like. Such overcoating layers are preferably selected so as notto substantially modify the wavelength emissions of the core. Thecomposition of quantum dots in the wavelength converter can be arrangedso at least some of the optical radiation with undesirable/lessdesirable wavelengths exhibiting relatively longer wavelengths areconverted into the first set of preferred wavelengths prior toconversion of that portion of the undesirable/less desirable wavelengthsexhibiting relatively shorter wavelengths. The wavelength converter maybe further adapted to conduct heat away from the light source. Thecontact element conveys at least some of the converted optical radiationto a one or more skin surfaces to facilitate the dermatologic treatment.

In yet another illustrative embodiment, the disclosed technology can beembodied within dermatologic treatment devices that facilitate one ormore dermatologic treatments of interest. The device includes a handheldhousing that contains a light source which emits optical radiationbeneficial to the dermatologic treatment(s). The housing also preferablyadapted to provide a haptic feedback to a user of the device thatsubstantially coincides with an application of the emitted opticalradiation to a skin surface during the dermatologic treatment.

In yet another illustrative embodiment, the disclosed technology can beembodied within a dermatologic treatment device that includes a lightsource (e.g., laser, light emitting diode, flashlamp, etc.) emittingoptical radiation beneficial to a dermatologic treatment and a userinterface that selectively operates the device in pulse mode or strobemode. In pulse mode, the light source emits a single optical radiationpulse to facilitate a spot treatment on a portion (e.g., 2 squarecentimeters) of a skin surface during the dermatologic treatment. Instrobe mode, the light source emits a continuous sequence of opticalradiation pulses to facilitate treatment of multiple locations on theskin surface during the dermatologic treatment. In one exemplaryimplementation, the duration of each pulse in the sequence can be 50 msand the interpulse delay can be one second.

In yet another illustrative embodiment, the disclosed technology can beembodied within a dermatologic treatment device that includes a lightsource, brightness enhancer, and replacement cartridge. The light source(e.g., laser, light emitting diode, flashlamp, etc.) emits opticalradiation that is beneficial to one or more dermatologic treatments andthe brightness enhancer enhances the brightness of at least some of thisemitted optical radiation. The replacement cartridge contains the lightsource and the brightness enhancer to facilitate their replacement by auser of the device between dermatologic treatments. The replacementcartridge is designed to be insertable into or removed from a handheldhousing of the device. The replacement cartridge can also be designedfor a particular skin type, which can be replaced prior to treating adifferent skin type and/or prior to treating different skin surfaces ofthe user during the same dermatologic treatment session.

In yet another illustrative embodiment, the disclosed technology can beembodied within a dermatologic treatment device that includes a lightsource, a reflector, a thermally conductive material, and a replacementcartridge. The light source emits at least some radiation which isbeneficial to one or more dermatologic treatments, including opticalradiation that exhibits a first set of wavelengths that are preferredfor the dermatologic treatment(s) and a second set of wavelengths thatare undesirable/less desirable for the treatment(s). The reflector isoptically coupled to the light source and reflects the emitted opticalradiation in a predetermined manner. The thermally conductive materialis in thermal communication with the light source and reflector andfacilitates a transfer of heat from the light source to the reflector.The thermally conductive material can include a composition of quantumdots adapted to convert at least some of the undesirable/less desirablesecond set of wavelengths into preferred first set of wavelengths. Thereplacement cartridge contains the light source, reflector, andthermally conductive material thereby facilitating the replacement ofthese components by a user of the device between dermatologictreatments. The replacement cartridge is insertable into/removable froma handheld housing of the device. The replacement cartridge can bedesigned for a particular skin type and may be further replaced prior totreating a different skin type and/or prior to treating different skinsurfaces of the user during the same dermatologic treatment session.

In yet another illustrative embodiment, the disclosed technology can beembodied within a dermatologic treatment device that includes a firstlight source, a second light source, and a timing circuit. The firstlight source emits a first pulse of optical radiation beneficial to adermatologic treatment. The second light source is optically coupled tothe first light source and emits a second pulse that enhances thebrightness of at least part of the optical radiation in the first pulseupon impinging on the first light source. The first pulse can furtherenhance the brightness of at least part of the optical radiation in thesecond pulse upon impinging on the second light source. The timingcircuit is adapted to energize the first and second light sources to atleast partially overlap emissions of the first and second pulses(resulting in, for example, a combined duration in the aggregate lightpulse actually conveyed to a skin surface of about 50 ms). The first andsecond light sources can be of the same or different type. The first andsecond pulses may also have one or more wavelengths in common or may notexhibit any common wavelengths. The device may further include a contactelement that is optically coupled to the first and second light sourcesand directs the at least partially overlapping emissions of the firstand second pulses to a skin surface during the dermatologic treatment.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing discussion will be understood more readily from thefollowing detailed description of the disclosed technology, when takenin conjunction with the accompanying drawings in which:

FIG. 1 provides a high-level block diagram of an illustrativedermatologic treatment device operated in accordance with the disclosedtechnology;

FIG. 2 provides an illustrative methodology for operating thedermatologic treatment device of FIG. 1;

FIG. 3 is a partial, three-dimensional representation of thedermatologic treatment device of FIG. 1 illustrating a preferredorientation and arrangement of its optical elements

FIG. 4 provides a cross-sectional representation of the optical elementsof the dermatologic treatment device of FIG. 1 illustrating an exemplaryconveyance of optical radiation using a brightness enhancer inconjunction with a vibrating contact element;

FIGS. 5A-D provide cross-sectional representations of severalillustrative arc-shaped, brightness enhancers that represent certainaspects of the disclosed technology;

FIGS. 6A-B provide cross-sectional representations of severalillustrative planar-shaped, brightness enhancers that represent certainaspects of the disclosed technology;

FIG. 7 provides a cross-sectional representation of an exemplary opticalsubsystem configuration in which multiple light sources are used inconjunction with a brightness enhancer;

FIGS. 8A-B are perspective drawings of an exterior of an illustrativehousing suitable for supporting the optical components of a dermatologictreatment device in accordance with certain aspects of the disclosedtechnology; and

FIG. 9 provides a cross-sectional representation of an exemplary lightreplacement cartridge that may be removable from/insertable into thehousing of FIG. 8 by a user of the dermatologic device in accordancewith certain aspects of the disclosed technology.

DETAILED DESCRIPTION

Unless otherwise specified, the illustrated embodiments can beunderstood as providing exemplary features of varying detail of certainembodiments, and therefore, unless otherwise specified, features,components, modules, elements, and/or aspects of the illustrations canbe otherwise combined, interconnected, sequenced, separated,interchanged, positioned, and/or rearranged without materially departingfrom the disclosed systems or methods. Additionally, the shapes andsizes of components are also exemplary and unless otherwise specified,can be altered without materially affecting or limiting the disclosedtechnology.

For the purposes of this disclosure, the term “subsystem” refers to aset of hardware and/or software elements that perform a desiredfunctionality. Those skilled in the art will recognize that thefunctionality described for a particular subsystem can be incorporatedinto one or more other subsystems and that the subsystems themselves canbe otherwise combined, separated, and/or organized without adverselyaffecting the operation of the disclosed technology and thus areintended merely for illustrative purposes. The term, “substantially” canbe broadly construed to indicate a precise relationship, condition,arrangement, orientation, and/or other characteristic, as well as,deviations thereof as understood by one of ordinary skill in the art, tothe extent that such deviations do not materially affect the disclosedmethods and systems. Further, the terms “light” and “optical radiation”are used interchangeably and references to “wavelengths” pertain tooptical radiation exhibiting wavelengths of the type described in thatcontext. The terms “device” and “system” are also used interchangeably.

The suitability of treating medical/aesthetic problems with opticalradiation has been investigated for several decades and spans a broadrange of treatment scenarios. Indeed many laser and flashlamp-basedsystems have been commercialized and designed for operation byexperienced health care professionals in the performance of both medicalprocedures (e.g., laser surgery, diagnosis and treatment of cancers,etc.) and cosmetic dermatologic treatment procedures (e.g., hairremoval, hair regrowth, skin rejuvenation, tattoo removal, treatment ofport-wine stains, etc.). The plethora of special and general-purposedevices that have been developed and commercialized by several industryparticipants coupled with stagnant market growth provide strong indiciathat the clinical light-treatment market is substantially saturated andhas matured.

In an effort to penetrate new market segments, some industryparticipants have recently focused their development efforts onproducing light-based, home-use products designed for treatment ofcosmetic dermatologic problems (e.g., removal of excess hair) byconsumers without requiring specialized health care training. Suchhome-use products are preferably designed to perform a single cosmeticdermatologic procedure at a relatively low cost and incorporate safetyand other design features to mitigate the risk of adverse affects tosubstantially untrained users. For example, a home-use, light-baseddevice for temporarily removing hair should be designed to providesufficient optical radiation to effect a desired change in the hairgrowth cycle without substantially damaging non-target tissue and whileconcurrently incorporating contact sensors, diffusing mechanisms, and/orother safety mechanisms to mitigate the risk of eye damage. Indeveloping commercially viable hair removal devices for the home-usemarket, it is also important to incorporate features into such devicesto enhance a user's experience when operating the device, such asemploying a sufficiently large treatment coverage area and a reasonablyquick treatment rate so that a user can treat large areas of skin in ashort period of time, along with sensation inhibition technology toreduce the amount of pain experienced by the user during treatment,mobility technology to enhance a user's ability to move and manipulatethe device while treating different skin surfaces, etc. The commercialsuccess of such home-uses devices is largely dependent on providing theabove features in a relatively small and inexpensive package.

As will be appreciated by those skilled in the art, providing aneffective, safe, and feature-rich, home-use device in a small andrelatively inexpensive package presents significant challenges andrequires careful balancing of design choices. For example, designtradeoffs for a light-based temporary hair removal device for home-usemay involve balancing the efficiency of the optical subsystem andability to generate optical radiation of sufficient characteristics totreat various skin types versus cost of optical components andassociated power, cooling, filtering, weight, and size requirements.Device costs generally increase with optical components exhibitingrelatively high efficiencies, light sources providing optical radiationat preferred wavelengths with reduced filtering requirements, powercomponents requiring greater output power and stringent pulse formingcapabilities, effective techniques for high temperature coolingapplications (liquid cooling being more complex and expensive than aircooling), etc.

In brief overview, an exemplary implementation of the disclosedtechnology can be used to develop such safe, effective, comfortable, andlow cost hair growth management/removal devices by a) employing arelatively low-efficiency, low cost, multi-wavelength light sourcesuitable for treating multiple skin and hair types, b) increasing theefficiency of the light source using light recycling techniques toenhance its brightness (i.e., spectral radiance) and thereby reducepower and filter requirements, c) optionally converting opticalradiation exhibiting undesired wavelengths into preferred wavelengths(while, preferably, integrating the optical radiation such that itexhibits a substantially uniform light distribution at substantially thesame time as the wavelength conversion), d) using a skin contactcomponent of the device for dual purposes—facilitating the conveyance ofoptical radiation and concurrently inhibiting a user's pain sensationduring the dermatologic treatment, e) providing multiple operating modesto cover spot treatments or large area treatments, and/or f) providing amechanism that both facilitates movement of the device over a skintreatment surface by reducing the coefficient of friction at theskin-device interface without use of messy gels/lotions and concurrentlydiffuses the optical radiation to mitigate the risk of potential eyedamage.

More particularly, the light source used in this illustrative embodimentis a flashlamp (e.g., xenon, krypton or the like) exhibiting anefficiency in wavelengths of interest of, for example, between about10-20% and emitting optical radiation having wavelengths at least in thenear infrared portion of the electromagnetic spectrum suitable for hairgrowth management/removal dermatologic treatments. The flashlamp is atleast partially surrounded by multiple reflective coatings that aredesigned to reflect optical radiation exhibiting wavelengths that arenot desired (e.g., ultraviolet) for the dermatologic treatment back tothe plasma of the flashlamp while allowing preferred wavelengths (e.g.,near infrared) to pass substantially unimpeded. In this manner, thereflective coatings provide a mechanism that both reflectively filtersout a substantial amount of unwanted wavelengths and recycles theseunwanted wavelengths so that they are superposed on the directly-emittedoptical radiation to increase the brightness (spectral radiance) of theoptical radiation, thereby resulting in an improved efficiency in theflashlamp without providing additional electrical current to theflashlamp. This technique of superposing unwanted radiation back ontothe directly-emitted optical radiation emitted by the light sourcepreferably results in a flashlamp efficiency in the wavelengths ofinterest that significantly exceeds 20%. The improved efficiency of thelight source in the wavelengths of interest improves the efficacy of thedevice in performing the dermatologic treatment and reduces the size andcapacity requirements of the power supply that is used to energize theflashlamp—resulting in reduced cost and size in the overall dermatologictreatment device.

The reflective coatings can be positioned on the inside or outsidesurface of the flashlamp itself, on the inside or outside surfaces of atube surrounding the flashlamp, on a planar surface of an opticalwaveguide (e.g., a light pipe with a quadrilateral cross-section)receiving the emitted optical radiation, or in any other manner in whichat least some optical radiation can be reflected back to the lightsource. In some embodiments, the reflection of optical radiation back tothe light source may involve a single coating that reflects only a smallportion of the unwanted radiation back to the source. In otherembodiments, a reflector that partially surrounds the flashlamp can bepolished aluminum, silver, gold or other type of reflector that reflectsback substantially all of the wavelengths impinging on its reflectivesurface. Regardless of implementation details, the above light recyclingtechnique increases the efficiency of a relatively low-cost andotherwise inefficient (in the wavelength band of interest) opticalradiation source beyond its capabilities in normal operation and therebyimproves performance of the optical subsystem while simultaneouslyreducing power, filtration, and other costs of the overall dermatologictreatment device. Any undesirable wavelengths that unwittingly pass bythe reflective coatings can be, optionally, converted to desiredwavelengths by subjecting these undesirable wavelengths to suitablephosphors, quantum dot materials or conveying such radiation through anoptical waveguide doped with such quantum dots or other luminescentdopant materials designed to convert such undesired wavelengths topreferred wavelengths. Alternatively, the undesired wavelengths may befiltered out using one or more absorptive or reflective filters.

The illustrative embodiment described above can further include anoptically-transparent, skin contact element that is placed substantiallyin physical contact with a skin surface during the dermatologictreatment. The contact element (e.g., a glass or plastic windowsupported within a handheld housing) facilitates conveyance of theoptical radiation to the skin surface, while concurrently providing avibration to the skin surface and/or surrounding skin surfaces so as toreduce the user's sensation of pain during the dermatologic treatmentpursuant to the Gate Theory of Afferent Inhibition. This contact elementmay further include a hydrophilic substrate coating on the skincontacting surface that substantially reduces the coefficient offriction at the skin-device interface when exposed to water, therebyfacilitating movement of the device between skin treatment regions. Uponexposure to water, this normally clear hydrophilic coating can appearcloudy and will thus further diffuse the optical radiation prior to itsapplication to the skin surface resulting in greater safety frompotential eye damage. The hydrophilic coating can also be formulated tofilter out ultraviolet and other unwanted wavelengths. The contactelement is also preferably adapted to be user-replaceable such that itcan be periodically replaced when, for example, the optical propertiesof the element degrade, the element exhibits physical wear, a usercompletes a dermatologic treatment session (replacement reduces cleanupeffort following the treatment and is more sanitary), the dermatologictreatment device is applied to the skin surface of a different user(again, replacement in such situations is more sanitary).

With reference now to FIG. 1, at least some aspects of the disclosedtechnology can be embodied within an illustrative hair growthmanagement/removal device 100. The device 100 preferably includes a UserInterface and Control Subsystem 102 that detects a user's intention tooperate the device 100 and, in response, enables a Power Subsystem 104to energize an Optical Subsystem 106 that generates and applies thedesired optical radiation to the skin surface targeted for hair growthmanagement, along with energizing a Sensor Subsystem 108 that ensuresthe safe operation of the device 100 and a Sensation-InhibitionSubsystem 110 that is adapted to inhibit the pain or other sensationexperienced by the user of the device 100 during the dermatologictreatment.

The User Interface and Control Subsystem 102 preferably includes a modeselection capability such that the device 100 selectively operates ineither pulse mode or strobe mode. In pulse mode, the User Interface andControl Subsystem 102 enables the Power Subsystem 104 to dischargesufficient electrical energy to the Optical Subsystem 106 such that asingle pulse of optical radiation is generated and applied to a targetskin surface. Conversely, in strobe mode, the User Interface and ControlSubsystem 102 enables the Power Subsystem 104 to discharge electricalenergy to the Optical Subsystem 106 at a preferably predetermined rate(e.g., one second inter-pulse intervals at a duration of between about10-50 milliseconds per pulse) such that optical radiation is generatedin a continuous sequence of corresponding light pulses. The intervalbetween such light pulses is preferably sufficient to enable the user ofthe device 100 to apply each subsequent pulse to substantially adjacentskin surfaces so that a relatively large region of skin can be quicklysubjected to the desired dermatologic treatment in a substantiallygliding motion. A one second inter-pulse interval is preferred in bothachieving this gliding motion and in providing a sufficient thermalrelaxation time to prevent undesired tissue damage to treated skinsurfaces in the event the user mistakenly applies multiple pulses to thesame skin surface without providing sufficient time for the treated skinto dissipate its excess heat. In other illustrative embodiments, theUser Interface and Control Subsystem 102 can enable the Power Subsystem104 to discharge electrical pulses to the Optical Subsystem at a ratedependent on a user's movement of at least part of the device 100.

The illustrative User Interface and Control Subsystem 102 describedabove also enables the Power Subsystem 104 to energize the SensorSubsystem 108, which, for example, detects whether the variouscomponents of the device 100 are operating within specified parameters(e.g., sense and evaluate the characteristics of emitted opticalradiation and/or characteristics of optical radiation reflected backfrom the skin surface under treatment, etc.) and/or whether the device100 is being properly operated by the user during the dermatologictreatment (e.g., sense whether at least part of the device 100 is inphysical contact with the skin surface during treatment, etc.).Exemplary elements of the Sensor Subsystem 108 capable of confirmingsuch physical contact may include one or more contact switches,capacitive sensors, resistive sensors, etc.

Similarly, the User Interface and Control Subsystem 102 enables thePower Subsystem 104 to energize the Sensation-Inhibition Subsystem 110,which preferably includes vibrating elements in physical contact withskin contact surfaces of the device 100 (e.g., one or more elements ofthe Optical Subsystem 106 and/or with a housing enclosing at least partof the device 100, etc.), such that vibrations of a sufficient magnitudeand at a sufficient frequency (e.g., 5700 vibrations per minute) areapplied to the skin surface under treatment and/or to substantiallyadjacent skin surfaces so as to reduce the user's overall sensation(e.g., sensations of pain, tingling, heat, etc.) during the dermatologictreatment. The vibrations applied to the skin surface by the device 100can be continuous during the operation of the device 100 (including, forexample, during a user's movement of parts of the device over the skinsurface), can be restricted to a time interval that correspondssubstantially to the same time interval and duration of the light pulsewhen applied to the skin surface, or can be applied during a timeinterval that begins shortly before the beginning of the light pulse andend shortly after the end of the light pulse (e.g., duration of lightpulse +10 ms on each side thereof). The vibrations can further providehaptic feedback to the user of the device 100 so that the user canreadily discern that a particular skin surface has been treated and thatat least part of the device should therefore be moved to another skinsurface. This haptic feedback is of particular relevance in situationswhere the vibrations dull the user's sensations in a particular skinsurface/region to a degree that the user feels little or substantiallyno sensation from application of the light pulse to that skinsurface/region and/or in situations where the light pulse applied to theskin surface/region contains one or more wavelengths that may not bedetectable by the human eye. Illustrative embodiments of the SensorSubsystem 108 and Sensation-Inhibition Subsystem 110 are furtherdescribed below in connection with FIG. 4.

The User Interface and Control Subsystem 102 is further adapted toreceive feedback from the Power Subsystem 104, Sensor Subsystem 108,and/or Sensation-Inhibition Subsystem 1 10 and provide discernibleindicia of at least some of the operating parameters of one or more ofthese subsystems to the user of the device 100. For example, mode (e.g.,pulse mode, strobe mode, etc.), status (e.g., device operational,sufficient contact at skin-device interface, etc.), and/or error/faultinformation (e.g., component of one or more subsystems requiresreplacement, etc.) can be conveyed to the user via visible (e.g., LCD orother display types, illumination of one or more LEDs, etc.), audible(e.g., beeps, synthesized speech, recorded speech, etc.), haptic (e.g.,vibration or other type of tactile stimulus), and/or any other type ofuser-discernible indicia.

The Power Subsystem 104 can be a line-powered supply which convertsalternating current to one or more direct currents suitable foroperating the various subsystems 102-1 10 of the device 100 or it can bea battery-powered supply with/without a line-power recharge capabilitythat is adapted to convert direct current exhibiting a first amplitudeto one or more other amplitudes as required by the various subsystems102-110. Regardless of the source of electrical energy, the PowerSubsystem 104 is preferably adapted to accommodate both the relativelylow power requirements of the User Interface and Control Subsystem 102,Sensor Subsystem 108, and Sensation-Inhibition Subsystem 110 and themuch greater power requirements of the Optical Subsystem 106. Forexample, the Power Subsystem 104 may include one or more power supplieswith power transformation, rectification, regulation, and/orconditioning circuits, along with high voltage capacitors (in the caseof flashlamp embodiments) and/or pulse forming circuitry to driveelements of the Optical Subsystem 106. The design of a suitable PowerSubsystem 104 is well within the understanding of those skilled in theart and, therefore, is not given any further treatment in thisdisclosure.

An illustrative Optical Subsystem 106 includes a) one or more lightsources 112 capable of generating optical radiation suitable for hairgrowth management/removal or other dermatologic treatment, b) one ormore brightness-enhancers 114 that enhance the brightness of the opticalradiation emitted by the light sources 112 and therefore increase itsoverall efficiency, c) one or more reflectors 116 (made of, for example,polished aluminum, gold, silver or other type of metallic or nonmetallicreflecting element, and shaped as a parabaloid, ellipsoid, or othersuitable shape) adapted to reflect the normal and enhanced opticalemissions of the light sources 112, d) one or more optical waveguides120 (e.g., glass or plastic light pipes exhibiting a quadrilateral crosssection, hollow optical waveguides with reflective internal surfaces, orany other type of elements that can efficiently convey opticalradiation) preferably adapted to exhibit a relatively high totalinternal reflectance and which efficiently receive and convey opticalradiation from the reflectors 116, and/or e) one or more contactelements 122 (made of glass, sapphire, plastic, or other materials thatare optically transparent to wavelengths of interest and which may beformed in a variety of shapes and surfaces, e.g., flat, convex, concave,etc.) adapted to be placed in substantial proximity to a skin surfaceunder treatment. In some embodiments, the contact elements 122 can be ametallic, plastic, or other type of support structure that maintains adesired distance between at least part of the device 100 and the skinsurface under treatment to thereby ensure that the desired amount ofoptical radiation is being applied to the skin surface. The OpticalSubsystem 106 may optionally include one or more reflective orabsorptive filters 118 to substantially remove or reduce unwantedwavelengths from the emitted optical radiation to the extent that suchunwanted wavelengths exceed a desired threshold and are not otherwiseeliminated, reduced, or converted by the brightness-enhancers 114,optical waveguides 120, contact elements 122 and/or wavelengthconverters (not shown).

Exemplary light sources 112 can include one or more flashlamps, lasers,LEDs, or other sources of optical radiation in substantially anysuitable quantity, configuration, or combination thereof. For clarity,the bulk of this disclosure will focus on flashlamp embodiments, butthis should not be misconstrued to imply that other types of lightsources cannot be used. An exemplary light source 112 can be a kryptonor xenon flash lamp exhibiting optical radiation emissions thatpreferably include peaks in the near infrared region of theelectromagnetic spectrum, which is preferred for hair growthmanagement/removal dermatologic treatments. In order to maintain a smallsize and relatively low cost in a handpiece (not shown) of a device 100designed for home use (the housing of the handpiece preferably containsthe light source 112), the Power Subsystem 104 can be configured tooverdrive the light source 112, thereby reducing the usable life of thelight source 112 in favor of maintaining a small size and desiredfluence levels (e.g., 5-10 Joules/centimeter squared for temporary hairgrowth management), while incurring a relatively low replacement costfor the flashlamp light source 112. The degree to which the flashlamplight source 112 is overdriven can be designed not only to meet theefficacy requirements of a particular dermatologic procedure, but alsoto effectively support a minimum number of dermatologic treatmentsbefore being replaced. Replacement of the relatively inexpensive lightsource 112 can be facilitated by packaging the flashlamp light source112 in a replaceable cartridge that can be readily inserted into/out ofthe housing of the device's handpiece. In this illustrative embodiment,a planned replacement interval (based on, for example, the number oftimes the light source 112 has been energized, the number ofdermatologic treatment sessions performed, etc.) for the flashlamp lightsource 112 enables the light source 112 to operate at substantially peakefficiency without experiencing an otherwise slow degradation inperformance potentially resulting in a reduced efficacy in thedermatologic procedure. Other embodiments may involve operating thelight source 112 in accordance with its standard operating parametersthat would extend the lifespan of the light source 112 at the expense ofa larger size in the light source and a slow degradation in performance.

As described previously, an illustrative brightness-enhancer 114 can beemployed to reflect some of the optical radiation emitted by the lightsource 112 (e.g., unwanted wavelengths) back to the light source 112 soas to increase the brightness of such source 112 (without requiringadditional electrical drive energy to the light source 112) and therebysubstantially increase the efficiency of the flashlamp light source 112(with respect to the desired wavelengths of about 600-1100 nanometers)and filter out some of the unwanted wavelengths (e.g., below 600 nmand/or above 1100 nm) at the same time. The brightness-enhancer 114 caninclude multiple coatings of reflective materials that are preferablyoptimized to reflect particular unwanted wavelengths and may be arrangedin substantially any desired shape using, for example, chemical vapordeposition processes. Illustrative orientations of suchbrightness-enhancers 114 are further described below in connection withFIGS. 3-6.

In one illustrative operation and with reference now also to FIG. 2, theSensor Subsystem 108 detects a contact signal generated when the contactsensors of the device 100 are triggered indicating when the device 100is in physical contact with the skin surface targeted for dermatologictreatment (202). In response to receiving an indication of the contactsignal from the Sensor Subsystem 108, the User Interface and ControlSubsystem 102 enables the Power Subsystem 104 to energize the vibrationelement of the Sensation-Inhibition Subsystem 110 so as to applysensation-inhibition stimuli to the skin surface to be treated (204). Insome embodiments, the vibration element may be energized upon poweringup the device 100 and prior to detection of the contact signal. The UserInterface and Control Subsystem 102 further enables the Power Subsystem104 to energize the light source 112 so that it emits a light pulse, ora sequence of continuous light pulses (206). Depending on the particularbrightness-enhancer 114 implemented in the device 100, at least some ofthe emitted optical radiation will be reflected back and superposed ontothe directly emitted optical radiation from the light source 112 so asto enhance the brightness of the light source 112 (208). Thedirectly-emitted optical radiation and the brightness-enhanced opticalradiation is received and reflected by the reflector 116 towards aninput face of the optical waveguide 120 (210). The filter 118 can thenfilter out at least some of the undesired wavelengths from the opticalradiation and/or at least some of the undesired wavelengths can beconverted into desirable wavelengths (using, for example, phosphormaterial, quantum dot material, and/or luminescent dopant materialembedded in the optical waveguide 120) (212). The optical waveguide 120or any other type of optical integrator (e.g., spherical reflector)improves the uniformity of the optical radiation it conveys to avoidoptical hot spots (214). The optical radiation transmitted through atleast one output face of the optical waveguide 120 can be optionallydiffused by, for example, passing the optical radiation through adiffusing portion of the contact element 122 (216). The opticalradiation is preferably applied to the skin surface via the contactelement 122 which is substantially in contact with the skin surface(218).

A particularly advantageous embodiment of an Optical Subsystem 302 isillustrated in FIG. 3. The light source 304 is preferably one or morexenon or krypton flashlamps (only one shown for clarity). The lightsource 304 is substantially surrounded by a tubular brightness-enhancingelement 306 exhibiting multiple reflective coatings 308 adapted tosubstantially reflect undesired wavelengths 310 and pass preferredwavelengths 312. The enhancing element 306 is preferably sized to leavesufficient space between the outer diameter of the light source 304 andthe inner diameter of the enhancing element 306 to enable the flow ofcooling air to remove excess heat from the light source 304 andenhancing element 306.

The preferred wavelengths 312, which include directly emitted opticalradiation and brightness-enhanced optical radiation, successfully passthrough the reflective coatings 308 of the enhancing element 306 and arereflected by an ellipsoid reflector 314 (whose reflective surfaces may,for example, include gold, silver, aluminum, etc.) towards an optionalfilter 316 and then on to a light pipe 318. The preferred wavelengths312 may pass through the enhancing element 306 once (see light ray 320)or be reflected by the reflector 314 back through the enhancing element306 one or more times prior to reaching the filter 316 and light pipe318 (see light ray 322). In some instances, any such preferredwavelengths 312 that are reflected back through the enhancing element306 may either again pass substantially unimpeded through the enhancingelement 306 or be absorbed by the light source 304 and thereby alsocontribute to the enhanced brightness of subsequently-emitted opticalradiation.

Some of the undesired wavelengths 310 may be able to escape thereflective filtering effect of the enhancing element 306 (see light ray324) and will be substantially and absorptively filtered by the filter316, light pipe, and/or contact element 326. Alternatively, or inconjunction, any such escaped optical radiation (e.g., light ray 324)can be subjected to one or more fluorophores, such as a phosphormaterial or other wavelength converter 328 (e.g., quantum dots,luminescent dopant material, etc.) embedded in the light pipe 318 toconvert the undesired wavelengths of the escaped optical radiation 324into preferred wavelengths (see converted-radiation light ray 330).

In an illustrative embodiment, where the wavelengths of the preferredlight 312 are in the range of about 600 nm-1100 nm and the light source304 also emits undesired light 310 on both sides of this range, thedisclosed technology can be used to reflect that portion of theundesired light 310 exhibiting wavelengths longer than 1100 nm back tothe light source 304 to increase overall brightness and the portion ofthe undesired light 310 exhibiting wavelengths shorter than 600 nm canbe converted into longer wavelengths within the range of the preferredlight 312 by the wavelength converter 328. For example, the undesiredlight 310 exhibiting wavelengths shorter than 600 nm can be converted tolonger wavelengths in the near infrared part of the electromagneticspectrum (NIR wavelengths are preferred for hair growthmanagement/removal) by passing such shorter wavelengths through quantumdot compositions that are tuned (with respect to composition, size,and/or shape) to emit desired wavelengths. Exemplary quantum dotcompositions that may be used to emit near infrared optical radiationcan include a core comprised of CdTe, InAs, InP, InSb, PbS, and/or PbSeand are preferably encapsulated in an overcoating layer (e.g., ZnS,ZnSe, GaN, MgS, MgSe, MgTe, CdS, or CdSe), which preferably enhancesefficiency, quantum yield, and photostability without substantiallymodifying the wavelength emissions of the core. Quantum dot compositionsmay be substantially homogeneous in size, shape, or core/overcoatelements in embodiments in which a relatively narrow set of emissionwavelengths are desired or can be heterogeneous in embodiments requiringa somewhat broader set of emission wavelengths. In an illustrativeheterogeneous implementation, it may be preferable to have incidentlight impinge first on quantum dots that emit the longest wavelengthsdesired and subsequently impinge on other quantum dots whose desiredemissions are successively shorter in wavelength. In this manner, therelatively longer wavelength emissions of a first layer of quantum dotmaterial will not be adversely affected by subsequent layers that couldotherwise reabsorb such wavelengths and emit other wavelengths. In someembodiments, heterogeneous implementations can reverse the order of suchlayers or intermix various combinations of quantum dots. In someembodiments, a wavelength selection element (e.g., one or more prisms,diffraction gratings, interference filters, etc.) (not shown) may beused to separate at least some of the undesired light (e.g., wavelengthsshorter than 600 nm) from the other optical radiation emissions of thelight source 304 and then subject such separated, undesired light toappropriate quantum dot compositions to provide a wavelength conversioneffect without substantially converting any of the other wavelengths.

The optical radiation 332 exiting the output face of the light pipe 318preferably exhibits a uniform illumination to avoid any undesiredradiation hot spots. This uniformly illuminated radiation 332 is passedthrough the contact element 326, which may include a hydrophilicsubstrate coating 334 at the skin-device interface to facilitatemovement of the dermatologic treatment device over or to the skinsurface/region targeted for treatment. The hydrophilic substrate 334 canbe formulated, in some embodiments, to filter out ultraviolet or otherundesired wavelengths 324 that escaped filtration/conversion by otherelements of the Optical Subsystem 302.

A cross-sectional view of the Optical Subsystem 302 of FIG. 3 isdepicted in FIG. 4 to more particularly illustrate exemplary locationsof contact sensors 402 and vibrating elements 404. The contact sensors402 can be mounted in a housing 406 forming a handpiece of thedermatologic treatment device and such sensors 402 can be positioned tocontact the skin 408 at a location that is substantially proximal to thecontact element 326 to thereby ensure that optical radiation emittedthrough the contact element 326 is substantially proximal to the skinsurface to be treated at the time of treatment. Alternatively, thecontact sensors 402 can be incorporated into or otherwise be physicallycoupled to the contact element 326. The exemplary vibrating elements 404are shown mounted between the housing 406 and the contact element 326,which contact element 326 may be mounted on a spring mechanism (notshown) to vibrationally separate the contact element 326 from thehousing 406, thereby causing the contact element 326 to provide the bulkof the sensation-inhibition stimuli to the skin rather than the housing406. Alternatively, the vibrating elements 404 can be configured tosubstantially vibrate that portion of the housing 406 that is in contactwith the skin 408 (which may or may not also cause the contact element326 to vibrate depending on the desired implementation) or may vibratethe entirety of the housing including portions that are and are not incontact with the skin 408.

With reference now to FIGS. 5A-D, several additional illustrativeembodiments are depicted for arc-shaped, brightness enhancers that maybe used to achieve the brightness-enhancement benefit described in thisdisclosure. These brightness enhancers can, in some cases, be adapted toreflect back all of the wavelengths in the impinging optical radiationor just subsets of wavelengths that are not desired for a particulardermatologic treatment, as previously described. Although thecross-sectional representations of the reflector 502, light source 504,and optical waveguide 506 depicted in each of FIGS. 5A-D are identical,those skilled in the art will recognize that a large variation in suchelements 502-506 can be implemented in different embodiments of adermatologic treatment device and that the sole purpose of showing theseelements 502-506 as being identical is to facilitate illustration ofdifferent orientations, configurations, and relative locations of thearc-shaped, brightness enhancers 508-514.

FIG. 5A depicts an arc-shaped brightness enhancer 508 that is configuredin a substantially hemispherical shape to cover that half of the lightsource 504 that faces the optical waveguide 506. In this embodiment, thebrightness enhancer can be formed as reflective coatings/film directlyin contact with an outer or inner surface of the quartz enclosure of theflashlamp light source 504 or can be formed on another material (e.g.,polished surface of a metallic hemispherical reflector, quartz supportmember with hemispherical shape, etc.) that is placed substantially incontact with the light source 504. This embodiment is also beneficial insituations where it is desired to periodically replace both the lightsource 504 and the enhancer 508 as a single unit to ensure peakperformance of the system during dermatologic treatments as previouslydescribed.

FIG. 5B depicts an arc-shaped brightness enhancer 510 that issubstantially similar to the hemispherical shape of the enhancer 508shown in FIG. 5A, except that it is located some distance away from theflashlamp light source 504 (e.g., far enough away so that any impingingoptical radiation will be substantially perpendicular at its point ofcontact and thus be optimally reflected back into the plasma of theflashlamp light source 504. The separation distance, whether optimal ornot, may also improve the cooling of the flashlamp 504 and/or enhancer510, and thereby extend the life of the flashlamp 504 and preventundesirable damage to the coatings of the enhancer 510. As with FIG. 5A,this FIG. 5B embodiment facilitates periodic replacement of the lightsource 504 and enhancer 510, except that it also provides the additionalbenefit of selectively being able to replace the light source 504 or theenhancer 510 separately or as a single light source-enhancer unit.

FIG. 5C depicts a variation of the arc-shaped brightness enhancer 510 ofFIG. 5B in that multiple enhancer elements 512 can be used in reflectingback some of the optical radiation emitted by the flash lamp 504 thatmay otherwise result in too many reflections by the reflector 502 priorto entering the optical waveguide 506. The particular design details forsuch enhancers 512 can be based on, for example, a threshold of how muchanticipated absorption is to be tolerated by the reflector 502 prior totransmitting the optical radiation to the optical waveguide 506.

FIG. 5D depicts an arc-shaped brightness enhancer 514 that is formed onan input face of the optical waveguide 506. Unlike the embodiments ofFIGS. 5A-C in which those enhancers 508-512 could be designed to eitherreflect back all impinging wavelengths or just wavelengths that are notdesired for a particular dermatologic treatment, the enhancer 514 ofthis embodiment must be designed to reflect back only some, but not allwavelengths, otherwise the emitted radiation would not be transmittedforward to the optical waveguide 506. Benefits of this embodiment,include maximizing cooling airflow between the light source 504 andenhancer 514 and/or reduced mounting support structures for the enhancer514.

With reference now to FIGS. 6A-B, several additional illustrativeembodiments are depicted for planar-shaped, brightness enhancers thatmay be used to achieve the brightness-enhancement benefit described inthis disclosure. As described above in connection with arc-shapedenhancers, these brightness enhancers can also be adapted to, in somecases, reflect back all of the wavelengths in the impinging opticalradiation or just reflect subsets of wavelengths that are not desiredfor a particular dermatologic treatment. Although the cross-sectionalrepresentations of the light source 604, and optical waveguide 606depicted in each of FIGS. 6A-B are identical, those skilled in the artwill recognize that a large variation in such elements 602-606 can beimplemented in different embodiments of a dermatologic treatment deviceand that the sole purpose of showing these elements 604-606 as beingidentical is to facilitate illustration of different orientations,configurations, and relative locations of the planar-shaped, brightnessenhancers 608-610.

FIG. 6A depicts a planar-shaped brightness enhancer 608 that is formedon an input face of the optical waveguide 606. Although the reflectionattributes of this enhancer 608 require that only some of thewavelengths be reflected back to the light source 604, this embodimentcan result in significant cost savings and reduce complexity in themanufacturing process for the enhancer 608 and will further maximize thevolume available for cooling airflow between the light source 604 andthe enhancer 606, as well as reducing the mounting support structuresfor the enhancer 608 and associated costs.

FIG. 6B depicts a planar-shaped brightness enhancer 612 that issubstantially similar to the planar shape of the enhancer 608 shown inFIG. 6A, except that it is spaced apart from both the flashlamp lightsource 604 and the optical waveguide 606 (the distances between suchenhancer 612 and elements 604, 606 may, but need not be equidistant). Aswith FIG. 5B, this FIG. 6B embodiment facilitates periodic replacementof the light source 604 and enhancer 612, separately or as a singlelight source-enhancer unit.

FIG. 7 depicts an illustrative embodiment in which multiple lightsources 702 (such as two or more flashlamps) are positionedsubstantially adjacent to each other and energized substantially at thesame time or during overlapping time intervals so that, for example, atleast some light emitted from light source 1 702′ impinges upon andthereby enhances the brightness of light source N 702″ and vice verse.Energizing flashlamp light sources 702′ and 702″ sequentially (e.g.,with substantially no inter-pulse delay or with an inter-pulse delayinterval that is less than the thermal relaxation time of a skin surfaceunder treatment) or with some overlap enables a particular skin surfaceto be treated for a relatively long duration of time without undulyoverdriving the light sources 702′ and 702″. A brightness enhancer 704can be positioned around at least part of the light sources 702 so as tofurther enhance the brightness of both light sources. The light sources702′ and 702″ may be adapted to emit optical radiation withsubstantially the same spectral characteristics, different spectralcharacteristics, or overlapping spectral characteristics. The lightsources 702′ and 702″ may further be of the same type (e.g., flashlamps)or of different types (e.g., combinations of flashlamps, lasers, and/orLEDs). The brightness enhancer 704 can be implemented in a variety ofshapes, sizes, orientations, and may further include more than onebrightness-enhancing element. In embodiments, where multiple brightnessenhancers are used, such brightness enhancers can have substantially thesame light reflecting effect on the light sources 702′ and 702″ or maybe designed to have different light reflecting effects on such lightsources 702′-702″. In some embodiments one or more brightness enhancersmay have an effect on light source 1 702′ but have substantially noeffect or a lessened effect on light source N 702–.

With reference to FIGS. 8A-B, at least some aspects of the disclosedtechnology can be incorporated within a handheld housing 800 of adermatologic treatment device. For example, the housing 800 preferablyencloses optical subsystem components with a surface of a contactelement 802 being exposed for placement against a skin surface to betreated. The housing includes cooling vents 804 that are used to draw inand/or exhaust cooling air applied to one or more of the components ofthe optical subsystem. User interface and control elements, such as anon/off switch 506 are provided in a location that is readily accessibleto a user during operation of the dermatologic treatment device. Thehousing 800 further contains contact sensors and sensation-inhibitionelements (not shown). In one illustrative embodiment, the housing 800includes a replaceable contact tip 808 that includes the contact element802. This replaceable contact tip 808 improves upon the sanitary use ofthe device by enabling a user to replace skin contact surfaces of thedevice between dermatologic treatments of the same/differentindividual(s) or during a single dermatologic treatment applied todifferent skin surfaces.

With reference now also to FIG. 9, the housing 800 of FIGS. 8A-Bpreferably includes a light-replacement cartridge 900 that is removablefrom/insertable into the housing 800 by a user of the dermatologicdevice in accordance with certain aspects of the disclosed technology.The light replacement cartridge 900 preferably includes one or morelight sources 902, a reflector 904, one or more brightness enhancers906, thermally conductive material 908 disposed at least between thelight sources 902 and the reflectors 904, and keyed housing guides 910adapted to ensure that the light replacement cartridge is of an approvedtype and is properly inserted into the housing 800 (FIG. 8) during areplacement procedure. The thermally conductive material 908 can be aliquid (such as water, a solution, suspension, etc.), a solid, and/or agas that is adapted to efficiently conduct heat from the light source902 to the reflector 904 (which subsequently transfers the heat to aheat sink and/or is air cooled), while concurrently conveying opticalradiation in a desired manner. The thermally conductive material 908 mayfurther be homogeneous or heterogeneous in its composition. Thethermally conductive material 908 may also include wavelength conversionmaterial (such as quantum dots) to convert undesired wavelengths emittedby the light source 902 into preferred wavelengths while concurrentlyusing at least some of any optical radiation backscattered from suchwavelength conversion material to further enhance the brightness of thelight source 902. The replacement procedure may be initiated, forexample, in the event that different skin types are to be treated (inwhich it may be desirable to insert optical components that areoptimized for such skin type), upon failure of the light source 902 orother system component, upon indication by a user interface and controlsubsystem, and/or upon release of improvements/corrections in the lightcartridge components made by a manufacturer thereof. Although thecartridge 900 may contain each of these components, those skilled in theart will recognize that the cartridge 900 may contain fewer components(such as, for example, only the light source 902, reflector 904, andthermally conductive material 908, or substantially any othercombination of components).

While a number of embodiments and variations thereon have been describedabove, it is intended that these embodiments are for purposes ofillustration only and that numerous other variations are possible whilepracticing the teachings of the disclosed technology. For example, thedisclosed technology has been largely described in connection with hairgrowth management/removal applications, but can be applied to a widevariety of medical or cosmetic dermatologic treatments. The particulartype, quantity, and orientation of optical radiation sources,brightness-enhancing elements, and other optical, mechanical, chemical,electrical, and/or physical aspects of the disclosed technology are alsoillustrative and can be readily modified without materially departingfrom the teachings of this disclosure. Thus, while the invention hasbeen particularly shown and described above with reference to preferredembodiments, the foregoing and other changes in form and detail may bemade therein by one skilled in the art without departing from the spiritand scope of the invention which is to be defined only by the appendedclaims.

1. A dermatologic treatment device, the device comprising: a lightsource emitting optical radiation having a plurality of wavelengths, theoptical radiation including light exhibiting at least a first set ofwavelengths and a second set of wavelengths, wherein the first set ofwavelengths is preferred for a dermatologic treatment; a wavelengthconverter converting at least some of the second set of wavelengths ofthe optical radiation to the first set of wavelengths; and a contactelement conveying at least some of the converted optical radiation to askin surface to facilitate the dermatologic treatment.
 2. The device ofclaim 1, wherein the light source is at least one of a flashlamp and alight emitting diode.
 3. The device of claim 1, wherein the first set ofwavelengths includes at least some wavelengths in the near infraredportion of the electromagnetic spectrum.
 4. The device of claim 3,wherein the second set of wavelengths are shorter than the first set ofwavelengths.
 5. The device of claim 4, wherein the wavelength converterincludes a composition of quantum dots having a core comprised of atleast one of CdTe, InAs, InP, InSb, PbS, and PbSe.
 6. The device ofclaim 5, wherein the core of the quantum dots is encapsulated in atleast one overcoating layer comprised of at least one of ZnS, ZnSe, GaN,MgS, MgSe, MgTe, CdS, and CdSe.
 7. The device of claim 6, wherein theovercoating layer does not substantially modify the wavelength emissionsof the core.
 8. The device of claim 1, wherein the wavelength converterincludes a composition of quantum dots arranged so that at least some ofthe second set of wavelengths of the optical radiation exhibitingrelatively longer wavelengths are converted into first set ofwavelengths prior to conversion of second set of wavelengths exhibitingrelatively shorter wavelengths.
 9. The device of claim 1, wherein thewavelength converter is further adapted to conduct heat away from thelight source.